Scala.js cross build

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# Scala.js cross build

[2016/01/30 Scala Matsuri](http://scalamatsuri.org/)

![CC-BY-NC-SA](https://licensebuttons.net/l/by-nc-sa/3.0/88x31.png)

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- twitter [@xuwei_k](https://twitter.com/xuwei_k)
- github [@xuwei-k](https://github.com/xuwei-k)
- blog <http://xuwei-k.hatenablog.com>

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## committer

- [scalaz](https://github.com/scalaz/scalaz)
- [scalikejdbc](https://github.com/scalikejdbc/scalikejdbc)
- [argonaut](https://github.com/argonaut-io/argonaut)
- [sbt-protobuf](https://github.com/sbt/sbt-protobuf)
- [json4s](https://github.com/json4s/json4s)
- [nscala-time](https://github.com/nscala-time/nscala-time)

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## My Libraries

- [scalaprops](https://github.com/scalaprops/scalaprops)
 - property based testing library
- [msgpack4z](https://github.com/msgpack4z)
 - functional msgpack libraries for Scala
- [httpz](https://github.com/xuwei-k/httpz)
 - purely functional http client with scalaz.Free
- [sbt-class-diagram](https://github.com/xuwei-k/sbt-class-diagram)
 - sbt plugin to create a class diagram
- [scalajspack](https://github.com/xuwei-k/scalajspack)
 - JSON to MessagePack converter powered by scala-js

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<https://twitter.com/not_ScalaMaturi/likes>
<https://github.com/xuwei-k/favorite_typo>

![not_ScalaMaturi](image/not_ScalaMaturi.png)

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<del>Scala Matsuri</del>

Scala.js Matsuri

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## <http://www.scala-js.org/>

write Scala => JavaScript!

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超有名な情報商材(?)

[![tototoshi](image/tototoshi-js.jpg)](http://tototoshi.github.io/slides/tenka1altjs-scalajs/)

@copyright [@tototoshi](https://twitter.com/tototoshi)

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## Scala.js and sbt

- <http://www.scala-js.org/doc/project/>
- <http://www.scala-js.org/doc/project/cross-build>

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project/plugin.sbt

```scala
addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.6")
```

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### JavaScript only

build.sbt

<pre>
<code class="scala hljs remark-code" style="font-size: 150%;">enablePlugins(ScalaJSPlugin)</code>
</pre>

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## [CrossType](https://github.com/scala-js/scala-js/blob/v0.6.6/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/cross/CrossType.scala)

1. Full
1. Pure
1. Dummy

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- since 0.6
- implemented by [@gzm0](https://github.com/gzm0)
- [Provide subset of scalaJSSettings for cross Scala/Scala.js modules](https://github.com/scala-js/scala-js/issues/1067)
- [Fix #1067: Add a simple CrossProject mechanism](https://github.com/scala-js/scala-js/pull/1346)

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both shared and individual JVM/JS sources

```scala
<project root>
 +- jvm
 | +- src/main/scala
 +- js
 | +- src/main/scala
 +- shared
 +- src/main/scala
```

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- default is Full
- [crossProject is macro](https://github.com/scala-js/scala-js/blob/v0.6.6/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/cross/CrossProject.scala#L330)

```scala
// This is NOT sbt.Project
lazy val foo = crossProject.in(file(".")).
  settings(
    name := "foo",
    scalaVersion := "2.11.7"
  ).jvmSettings(
    // Add JVM-specific settings here
  ).jsSettings(
    // Add JS-specific settings here
  )
```

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build.sbt

```scala
lazy val root = project.in(file(".")).
  aggregate(fooJS, fooJVM).
  settings(
    publish := {},
    publishLocal := {}
  )

lazy val fooJVM = foo.jvm
lazy val fooJS = foo.js
```

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- Does not have individual JVM/JS sources
- only generated files in `.jvm`, `.js`

```scala
<project root>
 +- src/main/scala
 +- .jvm/
 +- .js/
```

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- Does not have individual JVM/JS sources

```scala
lazy val foo =
  crossProject.crossType(CrossType.Pure)

lazy val fooJVM = foo.jvm
lazy val fooJS = foo.js
```

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Does not have shared JVM/JS sources

[`CrossType.Dummy`](https://github.com/scala-js/scala-js/blob/v0.6.6/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/cross/CrossProject.scala#L100-L116)

```scala
<project root>
 +- jvm
 | +- src/main/scala
 +- js
 +- src/main/scala
```

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I don't want to move many files...

JVM only project
```scala
<project root>
 +- src/main/scala
```

↓

cross build project
```scala
<project root>
 +- jvm
 | +- src/main/scala
 +- js
 | +- src/main/scala
 +- src/main/scala // not shared/src/main/scala
```

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[write your CrossType!](https://github.com/scala-js/scala-js/blob/v0.6.6/sbt-plugin/src/main/scala/scala/scalajs/sbtplugin/cross/CrossProject.scala#L193-L206)
```scala
object MyCrossType extends CrossType {
  def projectDir(crossBase: File, projectType: String) =
    crossBase / projectType

def sharedSrcDir(projectBase: File, conf: String) =
    Some(projectBase.getParentFile / "src" / conf / "scala")
} 
```

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- [Scala.jsに対応したscodec-msgpackをリリースしました - pocketberserkerの暴走](http://pocketberserker.hatenablog.com/entry/2015/11/30/100000)
- [support scala-js - scodec-msgpack pull request #6](https://github.com/pocketberserker/scodec-msgpack/pull/6)

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scodec-msgpackがやったなら msgpack4zもScala.js対応するか

↓

[scala-jsでBigIntegerのバグ見つけた](http://d.hatena.ne.jp/xuwei/20160110/1452441238)

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msgpack4zのテストにscalaprops使ってるから せっかくだしこれもやるか

↓

scalapropsはscalazに依存してるし scalazも公式でやるか

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## Coming soon ... ?

- [scalaz](https://github.com/scalaz/scalaz) & scala.js
- [scalaprops](https://github.com/scalaprops/scalaprops) & scala.js
- [msgpack4z](https://github.com/msgpack4z) & scala.js